Flashcards in Pharma Behaviour_Nitrous Sedation Deck (21):
What are the goals of nitrous sedation?
-Facilitate appropriate care of patient
-Decrease extremes of disruptive behavior
-Create a safer environment for patients/staff
-Bring the patient back to a psychological state which is safe for discharge
What are the indications for use of nitrous sedation?
-Patients mildly to moderately anxious
-Fear of needles
-Profound LA can't be obtained
-Older children with previous negative dental experience
-Child with special needs
-Complex or long procedures
*Patient needs to be medically fit
What are the pharmocodynamics of nitrous oxide sedation?
(Effect of drug on body)
-Unknown mechanism (thought to act on GABAA or opioid receptors)
-Results in chlorine influx and hyperpolarisation of neurons
-Thus require greater stimulation for action potential to be generated
What is are the pharmacokinetics of nitrous oxide?
(Effect of body on drug)
-Rapidly absorbed through alveoli and carried by serum throughout circulation via partial pressure gradient
-Insolubility of nitrous oxide means equilibrium can be achieved quickly/blood brain barrier crossed
-Insolubility also means N2O leaves bloodstream quickly and passes into other tissues
-Diffuses into closed air spaces such as middle air until equilibrium achieved
-Little to no biotransformation
-Not metabolised by liver
-99% eliminated through lungs (diffuse from CNS into bloodstream and exhaled from lungs)
-0.04% metabolised by GIT
-Small amounts excreted
-Rapid and repeat recovery after cessation
At what time after inhalation can the peak effects be expected?
What are the physical impacts of nitrous oxide?
-euphoric and depressant effects
-Pt should be relaxed and comfortable + acknowledge reduced fear
-Pt should be aware of surroundings
-Pt should be able to respond to instructions and converse
-Pt should be happy/in pleasant mood
-pharyngeal and laryngeal reflexes maintained
-Relaxation (shoulders drop, legs uncrossed, feet relaxed, etc.)
-Eyes initially alert, but lessen with sedation and blink rate slower
-Facial expression flat, may smile easier, no signs of tension
-Tingling in extremeities (not with all patients)
-Heaviness in thighs and legs
-Patient's voice may resonate or carry hypernasal tone
-Operator's voice may sound distant
-May feel warmth from vasodilation (but should be comfortable)
What are the contraindications for RA?
-Respiratory problems (COPD, asthma, cold, tonsilitis, nasal blockage, refusal to breathe through nose)
-GI bowel obstructin
-Otitis media or other middle ear problems
-Psychiatric disease (e.g. drug adddiction)
-Pregnancy (1st trimester)
-Fear of nasal hood or claustrophobia
What are some adverse effects of RA?
Usually due to overdose or poor patient vomitting
-Nausea and/or vomitting
-Visual disturbance, room spinning
What are some signs of over-sedation?
-Nausea and/or vomitting, dizziness, lightheadedness
-Visual disturbance, room spinning
-Detachment/dissociation from environment
-Inability to move, communicate, keep mouth open
-Dreaming hallucination or fantasizing
-Out of body experience (Floating and/or flying)
-Humming or vibrating sounds
-Keep close eye on patient
-Uncomfortable body warmth
How should N2O be induced?
-Begin with 100% O2, increase N2O concentration by 10% per minute until desiered effect
*Elder patients (vomit easier)
-INtroduced to 40% N2O
-Monitor 2-3 minutes
*Better for younger children but increased risk adverse effect
What should be done if signs of overdose are evident?
-Turn O2 to 100% if patient seleeps
-Avoid sudden changes/fluctuations
-Monitor patient closely
What are some precautions that shoudl be taken with RA?
-Appropriate training of those involved
-Do not leave patient unattended
-Two staff members always present
-Occupational health and safety
What are the components of equpiment used for RA?
-Gas delivery machine
-Oxygen flush valve
(Air flows through the machine in this order, except for oxygen flush valve. Flows from scavenging system into high speed suction)
What is the flow rate of the delivery machine?
T/F the numbers on the flowmetre shows %
It shows litres of flow per minute
What is the minimum threshold for oxygen levels before
What is the purpose of the reservoir bag?
-Provided additional gas if necessary
-Mechanism for monitoring pt respiration and adjusting flow
-Provides oxygen in emergency
What is the pre-op procedure for RA?
-Inform parents/ guardians and sign consent, give them RA pamphlet to read
-Make sure equipment set up properlly
-Patient must respond properly to tell-show-do for placing nasal hood and breathing
What should be done post-operatively?
-100% O2 button for 5 minutes to prevent hypoxia (flush button)
What should be recorded?
Signed informed consent
-Indcation for use
-Nitrous oxide dosage (percentage, flow rate, duration)